Computers Cisco CCNP BSCI 642-901 Exam: OSPF And Passive Interfaces
Passive interfaces accept routing updates, but do not send them. Regarding OSPF, even though OSPF does not sent "routing updates" in the form that RIP, IGRP, and EIGRP do, you can still configure an OSPF-enabled interface as passive in order to prevent OSPF traffic from exiting that interface. No OSPF adjacency can be formed if one of the interfaces involved is a passive interface, and if you configure an OSPF-enabled interface as passive where an adjacency already exists, the adjacency will drop almost immediately.
In the following example, R1 and R2 have an existing OSPF adjacency over their Ethernet interfaces. In an effort to reduce routing traffic, R1's e0 interface is configured as passive. The adjacency drops right away.
R1(config)#router ospf 1
R1(config-router)#passive-interface ethernet0
R1(config-router)#
18:31:11: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Ethernet0 from FULL to DOWN, Neighbor Down: Interface down or detached
That's a pretty important detail to keep in mind when you're using the passive-interface command, wouldn't you say?
You may well have a router that you want to configure most interfaces as passive. There's no longer a need to configure each interface as passive in that case - As of IOS version 12.0, you can now set all interfaces on a router as passive for a given protocol with the passive-interface default command. You can then configure each interface that you do NOT want to be passive with the "no passive-interface" command.
R3(config)#router ospf 1
R3(config-router)#passive-interface default
To set the interfaces back to their default, just use the no passive-interface default command.
R3(config-router)#no passive-interface default
The passive interface is a simple topic, but it can get a little tricky when you start changing the default and then start configuring interfaces on an individual level. Just be careful with this command on exam day and in the real world, and you'll succeed in the BSCI exam room and on real-world networks as well!
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage, home of free CCNA tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages. You can also visit his blog, which is updated several times daily with new Cisco certification articles, free tutorials, and daily CCNA / CCNP exam questions! Details are on the website. There are free BSCI exam with The Bryant Advantage!
Related Tags: cisco, ccnp, ospf, passive, bsci, 642-901, adjacency, interface, hello, ios
Your Article Search Directory : Find in Articles
Recent articles in this category:
- Fix Printer, Keyboard, Speaker and Monitor Cables With Funky Organizers
There are different types of cables that are used when you have a desktop computer at home. Most of - The Growing Trend of Asterisk Phone Systems
Truly, businesses are doing everything they can in the economy and competitive world of today to rem - The Future of Business Intelligence: Innovations in Location Intelligence
In the coming years, many business analysts are predicting that Business Intelligence (BI) will play - Adobe Photoshop Album Starter Edition and What Happened to the Unlock Codes
Adobe has long been known as a star in the digital image editing world and the Adobe Photoshop Album - Choosing the Best Computer For Graphic Design
In the 1980s, desktop publishing came out and graphic designers began to utilize computers for all k - Versatility of Pocket HD Camcorders
In the era of the do-everything handheld gadget, high def camcorders family seems almost passee. The - Contemporary Office Furniture
When considering Contemporary Office Furniture there are a few things that you really should conside - Professional Web Design, Professional Web Designer
There is a lot to consider if you are looking for a Professional Web Design. So let's get to it. Fir - Cell Phone Protection and Safety For Kids
If your like the millions of parents giving your children a cell phone for safety when their away fr - Looking For That Smart Pc Workstation And Desk
Do you need a work area at home. Maybe it is just for doing bills. It may be for a community work ar
Most viewed articles in this category:
- Voip Residential Comparison Guide: Evaluating Packet8, Lingo, And Vonage
Voice over internet protocol [internet telephony] is a rapidly growing technological alternative to - What's The Difference In The Ionic Breeze Quadra?
The Ionic Breeze Quadra is the newer line of ionic breeze units offered by The Sharper Image. These - Selling World of Warcraft Accounts
Everybody knows that WoW is one of the most exciting MMORPGs ever created. This makes selling WoW ac - Film Cameras
Film cameras are simple cameras, which could be used by all easily. People prefer to use film camera - Salesboom SLA-MS Competition
Oh, the irony. Online CRM Services shy away from offering customers a Service Level Agreement. Why t - How To Improve Your Computer Speed Almost Instantly
Probably your computer, even though you bought it last year its no longer that much fast. Like any o - The Mosquito Ringtone - The Tone Adults Can't Hear
Without a doubt, the mosquito ringtone is one of the most popular ringtones ever. Good luck trying - Auto Navigation Systems And Gps Technology While Traveling
If you have managed to do any research on auto navigation systems I'm sure you've come across countl - Do Cheap iPods Really Exist?
If you know anything about music trends, you know that iPods are the hottest portable music device t - Online Mobile Phone Offers: Take 10 Minutes To Save £360 On Your Next Mobile Phone Contract
Cash Is Falling Out Of Your Pocket If you live in the UK, you're probably paying line rental on a m